net/sched/sch_fq.c

   1 /*
   2  * net/sched/sch_fq.c Fair Queue Packet Scheduler (per flow pacing)
   3  *
   4  *  Copyright (C) 2013-2015 Eric Dumazet <edumazet@google.com>
   5  *
   6  *      This program is free software; you can redistribute it and/or
   7  *      modify it under the terms of the GNU General Public License
   8  *      as published by the Free Software Foundation; either version
   9  *      2 of the License, or (at your option) any later version.
  10  *
  11  *  Meant to be mostly used for locally generated traffic :
  12  *  Fast classification depends on skb->sk being set before reaching us.
  13  *  If not, (router workload), we use rxhash as fallback, with 32 bits wide hash.
  14  *  All packets belonging to a socket are considered as a 'flow'.
  15  *
  16  *  Flows are dynamically allocated and stored in a hash table of RB trees
  17  *  They are also part of one Round Robin 'queues' (new or old flows)
  18  *
  19  *  Burst avoidance (aka pacing) capability :
  20  *
  21  *  Transport (eg TCP) can set in sk->sk_pacing_rate a rate, enqueue a
  22  *  bunch of packets, and this packet scheduler adds delay between
  23  *  packets to respect rate limitation.
  24  *
  25  *  enqueue() :
  26  *   - lookup one RB tree (out of 1024 or more) to find the flow.
  27  *     If non existent flow, create it, add it to the tree.
  28  *     Add skb to the per flow list of skb (fifo).
  29  *   - Use a special fifo for high prio packets
  30  *
  31  *  dequeue() : serves flows in Round Robin
  32  *  Note : When a flow becomes empty, we do not immediately remove it from
  33  *  rb trees, for performance reasons (its expected to send additional packets,
  34  *  or SLAB cache will reuse socket for another flow)
  35  */
  36
  37 #include <linux/module.h>
  38 #include <linux/types.h>
  39 #include <linux/kernel.h>
  40 #include <linux/jiffies.h>
  41 #include <linux/string.h>
  42 #include <linux/in.h>
  43 #include <linux/errno.h>
  44 #include <linux/init.h>
  45 #include <linux/skbuff.h>
  46 #include <linux/slab.h>
  47 #include <linux/rbtree.h>
  48 #include <linux/hash.h>
  49 #include <linux/prefetch.h>
  50 #include <linux/vmalloc.h>
  51 #include <net/netlink.h>
  52 #include <net/pkt_sched.h>
  53 #include <net/sock.h>
  54 #include <net/tcp_states.h>
  55 #include <net/tcp.h>
  56
  57 /*
  58  * Per flow structure, dynamically allocated
  59  */
  60 struct fq_flow {
  61         struct sk_buff  *head;          /* list of skbs for this flow : first skb */
  62         union {
  63                 struct sk_buff *tail;   /* last skb in the list */
  64                 unsigned long  age;     /* jiffies when flow was emptied, for gc */
  65         };
  66         struct rb_node  fq_node;        /* anchor in fq_root[] trees */
  67         struct sock     *sk;
  68         int             qlen;           /* number of packets in flow queue */
  69         int             credit;
  70         u32             socket_hash;    /* sk_hash */
  71         struct fq_flow *next;           /* next pointer in RR lists, or &detached */
  72
  73         struct rb_node  rate_node;      /* anchor in q->delayed tree */
  74         u64             time_next_packet;
  75 };
  76
  77 struct fq_flow_head {
  78         struct fq_flow *first;
  79         struct fq_flow *last;
  80 };
  81
  82 struct fq_sched_data {
  83         struct fq_flow_head new_flows;
  84
  85         struct fq_flow_head old_flows;
  86
  87         struct rb_root  delayed;        /* for rate limited flows */
  88         u64             time_next_delayed_flow;
  89
  90         struct fq_flow  internal;       /* for non classified or high prio packets */
  91         u32             quantum;
  92         u32             initial_quantum;
  93         u32             flow_refill_delay;
  94         u32             flow_max_rate;  /* optional max rate per flow */
  95         u32             flow_plimit;    /* max packets per flow */
  96         u32             orphan_mask;    /* mask for orphaned skb */
  97         u32             low_rate_threshold;
  98         struct rb_root  *fq_root;
  99         u8              rate_enable;
 100         u8              fq_trees_log;
 101
 102         u32             flows;
 103         u32             inactive_flows;
 104         u32             throttled_flows;
 105
 106         u64             stat_gc_flows;
 107         u64             stat_internal_packets;
 108         u64             stat_tcp_retrans;
 109         u64             stat_throttled;
 110         u64             stat_flows_plimit;
 111         u64             stat_pkts_too_long;
 112         u64             stat_allocation_errors;
 113         struct qdisc_watchdog watchdog;
 114 };
 115
 116 /* special value to mark a detached flow (not on old/new list) */
 117 static struct fq_flow detached, throttled;
 118
 119 static void fq_flow_set_detached(struct fq_flow *f)
 120 {
 121         f->next = &detached;
 122         f->age = jiffies;
 123 }
 124
 125 static bool fq_flow_is_detached(const struct fq_flow *f)
 126 {
 127         return f->next == &detached;
 128 }
 129
 130 static void fq_flow_set_throttled(struct fq_sched_data *q, struct fq_flow *f)
 131 {
 132         struct rb_node **p = &q->delayed.rb_node, *parent = NULL;
 133
 134         while (*p) {
 135                 struct fq_flow *aux;
 136
 137                 parent = *p;
 138                 aux = container_of(parent, struct fq_flow, rate_node);
 139                 if (f->time_next_packet >= aux->time_next_packet)
 140                         p = &parent->rb_right;
 141                 else
 142                         p = &parent->rb_left;
 143         }
 144         rb_link_node(&f->rate_node, parent, p);
 145         rb_insert_color(&f->rate_node, &q->delayed);
 146         q->throttled_flows++;
 147         q->stat_throttled++;
 148
 149         f->next = &throttled;
 150         if (q->time_next_delayed_flow > f->time_next_packet)
 151                 q->time_next_delayed_flow = f->time_next_packet;
 152 }
 153
 154
 155 static struct kmem_cache *fq_flow_cachep __read_mostly;
 156
 157 static void fq_flow_add_tail(struct fq_flow_head *head, struct fq_flow *flow)
 158 {
 159         if (head->first)
 160                 head->last->next = flow;
 161         else
 162                 head->first = flow;
 163         head->last = flow;
 164         flow->next = NULL;
 165 }
 166
 167 /* limit number of collected flows per round */
 168 #define FQ_GC_MAX 8
 169 #define FQ_GC_AGE (3*HZ)
 170
 171 static bool fq_gc_candidate(const struct fq_flow *f)
 172 {
 173         return fq_flow_is_detached(f) &&
 174                time_after(jiffies, f->age + FQ_GC_AGE);
 175 }
 176
 177 static void fq_gc(struct fq_sched_data *q,
 178                   struct rb_root *root,
 179                   struct sock *sk)
 180 {
 181         struct fq_flow *f, *tofree[FQ_GC_MAX];
 182         struct rb_node **p, *parent;
 183         int fcnt = 0;
 184
 185         p = &root->rb_node;
 186         parent = NULL;
 187         while (*p) {
 188                 parent = *p;
 189
 190                 f = container_of(parent, struct fq_flow, fq_node);
 191                 if (f->sk == sk)
 192                         break;
 193
 194                 if (fq_gc_candidate(f)) {
 195                         tofree[fcnt++] = f;
 196                         if (fcnt == FQ_GC_MAX)
 197                                 break;
 198                 }
 199
 200                 if (f->sk > sk)
 201                         p = &parent->rb_right;
 202                 else
 203                         p = &parent->rb_left;
 204         }
 205
 206         q->flows -= fcnt;
 207         q->inactive_flows -= fcnt;
 208         q->stat_gc_flows += fcnt;
 209         while (fcnt) {
 210                 struct fq_flow *f = tofree[--fcnt];
 211
 212                 rb_erase(&f->fq_node, root);
 213                 kmem_cache_free(fq_flow_cachep, f);
 214         }
 215 }
 216
 217 static struct fq_flow *fq_classify(struct sk_buff *skb, struct fq_sched_data *q)
 218 {
 219         struct rb_node **p, *parent;
 220         struct sock *sk = skb->sk;
 221         struct rb_root *root;
 222         struct fq_flow *f;
 223
 224         /* warning: no starvation prevention... */
 225         if (unlikely((skb->priority & TC_PRIO_MAX) == TC_PRIO_CONTROL))
 226                 return &q->internal;
 227
 228         /* SYNACK messages are attached to a TCP_NEW_SYN_RECV request socket
 229          * or a listener (SYNCOOKIE mode)
 230          * 1) request sockets are not full blown,
 231          *    they do not contain sk_pacing_rate
 232          * 2) They are not part of a 'flow' yet
 233          * 3) We do not want to rate limit them (eg SYNFLOOD attack),
 234          *    especially if the listener set SO_MAX_PACING_RATE
 235          * 4) We pretend they are orphaned
 236          */
 237         if (!sk || sk_listener(sk)) {
 238                 unsigned long hash = skb_get_hash(skb) & q->orphan_mask;
 239
 240                 /* By forcing low order bit to 1, we make sure to not
 241                  * collide with a local flow (socket pointers are word aligned)
 242                  */
 243                 sk = (struct sock *)((hash << 1) | 1UL);
 244                 skb_orphan(skb);
 245         }
 246
 247         root = &q->fq_root[hash_32((u32)(long)sk, q->fq_trees_log)];
 248
 249         if (q->flows >= (2U << q->fq_trees_log) &&
 250             q->inactive_flows > q->flows/2)
 251                 fq_gc(q, root, sk);
 252
 253         p = &root->rb_node;
 254         parent = NULL;
 255         while (*p) {
 256                 parent = *p;
 257
 258                 f = container_of(parent, struct fq_flow, fq_node);
 259                 if (f->sk == sk) {
 260                         /* socket might have been reallocated, so check
 261                          * if its sk_hash is the same.
 262                          * It not, we need to refill credit with
 263                          * initial quantum
 264                          */
 265                         if (unlikely(skb->sk &&
 266                                      f->socket_hash != sk->sk_hash)) {
 267                                 f->credit = q->initial_quantum;
 268                                 f->socket_hash = sk->sk_hash;
 269                                 f->time_next_packet = 0ULL;
 270                         }
 271                         return f;
 272                 }
 273                 if (f->sk > sk)
 274                         p = &parent->rb_right;
 275                 else
 276                         p = &parent->rb_left;
 277         }
 278
 279         f = kmem_cache_zalloc(fq_flow_cachep, GFP_ATOMIC | __GFP_NOWARN);
 280         if (unlikely(!f)) {
 281                 q->stat_allocation_errors++;
 282                 return &q->internal;
 283         }
 284         fq_flow_set_detached(f);
 285         f->sk = sk;
 286         if (skb->sk)
 287                 f->socket_hash = sk->sk_hash;
 288         f->credit = q->initial_quantum;
 289
 290         rb_link_node(&f->fq_node, parent, p);
 291         rb_insert_color(&f->fq_node, root);
 292
 293         q->flows++;
 294         q->inactive_flows++;
 295         return f;
 296 }
 297
 298
 299 /* remove one skb from head of flow queue */
 300 static struct sk_buff *fq_dequeue_head(struct Qdisc *sch, struct fq_flow *flow)
 301 {
 302         struct sk_buff *skb = flow->head;
 303
 304         if (skb) {
 305                 flow->head = skb->next;
 306                 skb->next = NULL;
 307                 flow->qlen--;
 308                 qdisc_qstats_backlog_dec(sch, skb);
 309                 sch->q.qlen--;
 310         }
 311         return skb;
 312 }
 313
 314 /* We might add in the future detection of retransmits
 315  * For the time being, just return false
 316  */
 317 static bool skb_is_retransmit(struct sk_buff *skb)
 318 {
 319         return false;
 320 }
 321
 322 /* add skb to flow queue
 323  * flow queue is a linked list, kind of FIFO, except for TCP retransmits
 324  * We special case tcp retransmits to be transmitted before other packets.
 325  * We rely on fact that TCP retransmits are unlikely, so we do not waste
 326  * a separate queue or a pointer.
 327  * head->  [retrans pkt 1]
 328  *         [retrans pkt 2]
 329  *         [ normal pkt 1]
 330  *         [ normal pkt 2]
 331  *         [ normal pkt 3]
 332  * tail->  [ normal pkt 4]
 333  */
 334 static void flow_queue_add(struct fq_flow *flow, struct sk_buff *skb)
 335 {
 336         struct sk_buff *prev, *head = flow->head;
 337
 338         skb->next = NULL;
 339         if (!head) {
 340                 flow->head = skb;
 341                 flow->tail = skb;
 342                 return;
 343         }
 344         if (likely(!skb_is_retransmit(skb))) {
 345                 flow->tail->next = skb;
 346                 flow->tail = skb;
 347                 return;
 348         }
 349
 350         /* This skb is a tcp retransmit,
 351          * find the last retrans packet in the queue
 352          */
 353         prev = NULL;
 354         while (skb_is_retransmit(head)) {
 355                 prev = head;
 356                 head = head->next;
 357                 if (!head)
 358                         break;
 359         }
 360         if (!prev) { /* no rtx packet in queue, become the new head */
 361                 skb->next = flow->head;
 362                 flow->head = skb;
 363         } else {
 364                 if (prev == flow->tail)
 365                         flow->tail = skb;
 366                 else
 367                         skb->next = prev->next;
 368                 prev->next = skb;
 369         }
 370 }
 371
 372 static int fq_enqueue(struct sk_buff *skb, struct Qdisc *sch,
 373                       struct sk_buff **to_free)
 374 {
 375         struct fq_sched_data *q = qdisc_priv(sch);
 376         struct fq_flow *f;
 377
 378         if (unlikely(sch->q.qlen >= sch->limit))
 379                 return qdisc_drop(skb, sch, to_free);
 380
 381         f = fq_classify(skb, q);
 382         if (unlikely(f->qlen >= q->flow_plimit && f != &q->internal)) {
 383                 q->stat_flows_plimit++;
 384                 return qdisc_drop(skb, sch, to_free);
 385         }
 386
 387         f->qlen++;
 388         if (skb_is_retransmit(skb))
 389                 q->stat_tcp_retrans++;
 390         qdisc_qstats_backlog_inc(sch, skb);
 391         if (fq_flow_is_detached(f)) {
 392                 fq_flow_add_tail(&q->new_flows, f);
 393                 if (time_after(jiffies, f->age + q->flow_refill_delay))
 394                         f->credit = max_t(u32, f->credit, q->quantum);
 395                 q->inactive_flows--;
 396         }
 397
 398         /* Note: this overwrites f->age */
 399         flow_queue_add(f, skb);
 400
 401         if (unlikely(f == &q->internal)) {
 402                 q->stat_internal_packets++;
 403         }
 404         sch->q.qlen++;
 405
 406         return NET_XMIT_SUCCESS;
 407 }
 408
 409 static void fq_check_throttled(struct fq_sched_data *q, u64 now)
 410 {
 411         struct rb_node *p;
 412
 413         if (q->time_next_delayed_flow > now)
 414                 return;
 415
 416         q->time_next_delayed_flow = ~0ULL;
 417         while ((p = rb_first(&q->delayed)) != NULL) {
 418                 struct fq_flow *f = container_of(p, struct fq_flow, rate_node);
 419
 420                 if (f->time_next_packet > now) {
 421                         q->time_next_delayed_flow = f->time_next_packet;
 422                         break;
 423                 }
 424                 rb_erase(p, &q->delayed);
 425                 q->throttled_flows--;
 426                 fq_flow_add_tail(&q->old_flows, f);
 427         }
 428 }
 429
 430 static struct sk_buff *fq_dequeue(struct Qdisc *sch)
 431 {
 432         struct fq_sched_data *q = qdisc_priv(sch);
 433         u64 now = ktime_get_ns();
 434         struct fq_flow_head *head;
 435         struct sk_buff *skb;
 436         struct fq_flow *f;
 437         u32 rate, plen;
 438
 439         skb = fq_dequeue_head(sch, &q->internal);
 440         if (skb)
 441                 goto out;
 442         fq_check_throttled(q, now);
 443 begin:
 444         head = &q->new_flows;
 445         if (!head->first) {
 446                 head = &q->old_flows;
 447                 if (!head->first) {
 448                         if (q->time_next_delayed_flow != ~0ULL)
 449                                 qdisc_watchdog_schedule_ns(&q->watchdog,
 450                                                            q->time_next_delayed_flow);
 451                         return NULL;
 452                 }
 453         }
 454         f = head->first;
 455
 456         if (f->credit <= 0) {
 457                 f->credit += q->quantum;
 458                 head->first = f->next;
 459                 fq_flow_add_tail(&q->old_flows, f);
 460                 goto begin;
 461         }
 462
 463         skb = f->head;
 464         if (unlikely(skb && now < f->time_next_packet &&
 465                      !skb_is_tcp_pure_ack(skb))) {
 466                 head->first = f->next;
 467                 fq_flow_set_throttled(q, f);
 468                 goto begin;
 469         }
 470
 471         skb = fq_dequeue_head(sch, f);
 472         if (!skb) {
 473                 head->first = f->next;
 474                 /* force a pass through old_flows to prevent starvation */
 475                 if ((head == &q->new_flows) && q->old_flows.first) {
 476                         fq_flow_add_tail(&q->old_flows, f);
 477                 } else {
 478                         fq_flow_set_detached(f);
 479                         q->inactive_flows++;
 480                 }
 481                 goto begin;
 482         }
 483         prefetch(&skb->end);
 484         f->credit -= qdisc_pkt_len(skb);
 485
 486         if (!q->rate_enable)
 487                 goto out;
 488
 489         /* Do not pace locally generated ack packets */
 490         if (skb_is_tcp_pure_ack(skb))
 491                 goto out;
 492
 493         rate = q->flow_max_rate;
 494         if (skb->sk)
 495                 rate = min(skb->sk->sk_pacing_rate, rate);
 496
 497         if (rate <= q->low_rate_threshold) {
 498                 f->credit = 0;
 499                 plen = qdisc_pkt_len(skb);
 500         } else {
 501                 plen = max(qdisc_pkt_len(skb), q->quantum);
 502                 if (f->credit > 0)
 503                         goto out;
 504         }
 505         if (rate != ~0U) {
 506                 u64 len = (u64)plen * NSEC_PER_SEC;
 507
 508                 if (likely(rate))
 509                         do_div(len, rate);
 510                 /* Since socket rate can change later,
 511                  * clamp the delay to 1 second.
 512                  * Really, providers of too big packets should be fixed !
 513                  */
 514                 if (unlikely(len > NSEC_PER_SEC)) {
 515                         len = NSEC_PER_SEC;
 516                         q->stat_pkts_too_long++;
 517                 }
 518
 519                 f->time_next_packet = now + len;
 520         }
 521 out:
 522         qdisc_bstats_update(sch, skb);
 523         return skb;
 524 }
 525
 526 static void fq_flow_purge(struct fq_flow *flow)
 527 {
 528         rtnl_kfree_skbs(flow->head, flow->tail);
 529         flow->head = NULL;
 530         flow->qlen = 0;
 531 }
 532
 533 static void fq_reset(struct Qdisc *sch)
 534 {
 535         struct fq_sched_data *q = qdisc_priv(sch);
 536         struct rb_root *root;
 537         struct rb_node *p;
 538         struct fq_flow *f;
 539         unsigned int idx;
 540
 541         sch->q.qlen = 0;
 542         sch->qstats.backlog = 0;
 543
 544         fq_flow_purge(&q->internal);
 545
 546         if (!q->fq_root)
 547                 return;
 548
 549         for (idx = 0; idx < (1U << q->fq_trees_log); idx++) {
 550                 root = &q->fq_root[idx];
 551                 while ((p = rb_first(root)) != NULL) {
 552                         f = container_of(p, struct fq_flow, fq_node);
 553                         rb_erase(p, root);
 554
 555                         fq_flow_purge(f);
 556
 557                         kmem_cache_free(fq_flow_cachep, f);
 558                 }
 559         }
 560         q->new_flows.first      = NULL;
 561         q->old_flows.first      = NULL;
 562         q->delayed              = RB_ROOT;
 563         q->flows                = 0;
 564         q->inactive_flows       = 0;
 565         q->throttled_flows      = 0;
 566 }
 567
 568 static void fq_rehash(struct fq_sched_data *q,
 569                       struct rb_root *old_array, u32 old_log,
 570                       struct rb_root *new_array, u32 new_log)
 571 {
 572         struct rb_node *op, **np, *parent;
 573         struct rb_root *oroot, *nroot;
 574         struct fq_flow *of, *nf;
 575         int fcnt = 0;
 576         u32 idx;
 577
 578         for (idx = 0; idx < (1U << old_log); idx++) {
 579                 oroot = &old_array[idx];
 580                 while ((op = rb_first(oroot)) != NULL) {
 581                         rb_erase(op, oroot);
 582                         of = container_of(op, struct fq_flow, fq_node);
 583                         if (fq_gc_candidate(of)) {
 584                                 fcnt++;
 585                                 kmem_cache_free(fq_flow_cachep, of);
 586                                 continue;
 587                         }
 588                         nroot = &new_array[hash_32((u32)(long)of->sk, new_log)];
 589
 590                         np = &nroot->rb_node;
 591                         parent = NULL;
 592                         while (*np) {
 593                                 parent = *np;
 594
 595                                 nf = container_of(parent, struct fq_flow, fq_node);
 596                                 BUG_ON(nf->sk == of->sk);
 597
 598                                 if (nf->sk > of->sk)
 599                                         np = &parent->rb_right;
 600                                 else
 601                                         np = &parent->rb_left;
 602                         }
 603
 604                         rb_link_node(&of->fq_node, parent, np);
 605                         rb_insert_color(&of->fq_node, nroot);
 606                 }
 607         }
 608         q->flows -= fcnt;
 609         q->inactive_flows -= fcnt;
 610         q->stat_gc_flows += fcnt;
 611 }
 612
 613 static void *fq_alloc_node(size_t sz, int node)
 614 {
 615         void *ptr;
 616
 617         ptr = kmalloc_node(sz, GFP_KERNEL | __GFP_REPEAT | __GFP_NOWARN, node);
 618         if (!ptr)
 619                 ptr = vmalloc_node(sz, node);
 620         return ptr;
 621 }
 622
 623 static void fq_free(void *addr)
 624 {
 625         kvfree(addr);
 626 }
 627
 628 static int fq_resize(struct Qdisc *sch, u32 log)
 629 {
 630         struct fq_sched_data *q = qdisc_priv(sch);
 631         struct rb_root *array;
 632         void *old_fq_root;
 633         u32 idx;
 634
 635         if (q->fq_root && log == q->fq_trees_log)
 636                 return 0;
 637
 638         /* If XPS was setup, we can allocate memory on right NUMA node */
 639         array = fq_alloc_node(sizeof(struct rb_root) << log,
 640                               netdev_queue_numa_node_read(sch->dev_queue));
 641         if (!array)
 642                 return -ENOMEM;
 643
 644         for (idx = 0; idx < (1U << log); idx++)
 645                 array[idx] = RB_ROOT;
 646
 647         sch_tree_lock(sch);
 648
 649         old_fq_root = q->fq_root;
 650         if (old_fq_root)
 651                 fq_rehash(q, old_fq_root, q->fq_trees_log, array, log);
 652
 653         q->fq_root = array;
 654         q->fq_trees_log = log;
 655
 656         sch_tree_unlock(sch);
 657
 658         fq_free(old_fq_root);
 659
 660         return 0;
 661 }
 662
 663 static const struct nla_policy fq_policy[TCA_FQ_MAX + 1] = {
 664         [TCA_FQ_PLIMIT]                 = { .type = NLA_U32 },
 665         [TCA_FQ_FLOW_PLIMIT]            = { .type = NLA_U32 },
 666         [TCA_FQ_QUANTUM]                = { .type = NLA_U32 },
 667         [TCA_FQ_INITIAL_QUANTUM]        = { .type = NLA_U32 },
 668         [TCA_FQ_RATE_ENABLE]            = { .type = NLA_U32 },
 669         [TCA_FQ_FLOW_DEFAULT_RATE]      = { .type = NLA_U32 },
 670         [TCA_FQ_FLOW_MAX_RATE]          = { .type = NLA_U32 },
 671         [TCA_FQ_BUCKETS_LOG]            = { .type = NLA_U32 },
 672         [TCA_FQ_FLOW_REFILL_DELAY]      = { .type = NLA_U32 },
 673         [TCA_FQ_LOW_RATE_THRESHOLD]     = { .type = NLA_U32 },
 674 };
 675
 676 static int fq_change(struct Qdisc *sch, struct nlattr *opt)
 677 {
 678         struct fq_sched_data *q = qdisc_priv(sch);
 679         struct nlattr *tb[TCA_FQ_MAX + 1];
 680         int err, drop_count = 0;
 681         unsigned drop_len = 0;
 682         u32 fq_log;
 683
 684         if (!opt)
 685                 return -EINVAL;
 686
 687         err = nla_parse_nested(tb, TCA_FQ_MAX, opt, fq_policy);
 688         if (err < 0)
 689                 return err;
 690
 691         sch_tree_lock(sch);
 692
 693         fq_log = q->fq_trees_log;
 694
 695         if (tb[TCA_FQ_BUCKETS_LOG]) {
 696                 u32 nval = nla_get_u32(tb[TCA_FQ_BUCKETS_LOG]);
 697
 698                 if (nval >= 1 && nval <= ilog2(256*1024))
 699                         fq_log = nval;
 700                 else
 701                         err = -EINVAL;
 702         }
 703         if (tb[TCA_FQ_PLIMIT])
 704                 sch->limit = nla_get_u32(tb[TCA_FQ_PLIMIT]);
 705
 706         if (tb[TCA_FQ_FLOW_PLIMIT])
 707                 q->flow_plimit = nla_get_u32(tb[TCA_FQ_FLOW_PLIMIT]);
 708
 709         if (tb[TCA_FQ_QUANTUM]) {
 710                 u32 quantum = nla_get_u32(tb[TCA_FQ_QUANTUM]);
 711
 712                 if (quantum > 0)
 713                         q->quantum = quantum;
 714                 else
 715                         err = -EINVAL;
 716         }
 717
 718         if (tb[TCA_FQ_INITIAL_QUANTUM])
 719                 q->initial_quantum = nla_get_u32(tb[TCA_FQ_INITIAL_QUANTUM]);
 720
 721         if (tb[TCA_FQ_FLOW_DEFAULT_RATE])
 722                 pr_warn_ratelimited("sch_fq: defrate %u ignored.\n",
 723                                     nla_get_u32(tb[TCA_FQ_FLOW_DEFAULT_RATE]));
 724
 725         if (tb[TCA_FQ_FLOW_MAX_RATE])
 726                 q->flow_max_rate = nla_get_u32(tb[TCA_FQ_FLOW_MAX_RATE]);
 727
 728         if (tb[TCA_FQ_LOW_RATE_THRESHOLD])
 729                 q->low_rate_threshold =
 730                         nla_get_u32(tb[TCA_FQ_LOW_RATE_THRESHOLD]);
 731
 732         if (tb[TCA_FQ_RATE_ENABLE]) {
 733                 u32 enable = nla_get_u32(tb[TCA_FQ_RATE_ENABLE]);
 734
 735                 if (enable <= 1)
 736                         q->rate_enable = enable;
 737                 else
 738                         err = -EINVAL;
 739         }
 740
 741         if (tb[TCA_FQ_FLOW_REFILL_DELAY]) {
 742                 u32 usecs_delay = nla_get_u32(tb[TCA_FQ_FLOW_REFILL_DELAY]) ;
 743
 744                 q->flow_refill_delay = usecs_to_jiffies(usecs_delay);
 745         }
 746
 747         if (tb[TCA_FQ_ORPHAN_MASK])
 748                 q->orphan_mask = nla_get_u32(tb[TCA_FQ_ORPHAN_MASK]);
 749
 750         if (!err) {
 751                 sch_tree_unlock(sch);
 752                 err = fq_resize(sch, fq_log);
 753                 sch_tree_lock(sch);
 754         }
 755         while (sch->q.qlen > sch->limit) {
 756                 struct sk_buff *skb = fq_dequeue(sch);
 757
 758                 if (!skb)
 759                         break;
 760                 drop_len += qdisc_pkt_len(skb);
 761                 rtnl_kfree_skbs(skb, skb);
 762                 drop_count++;
 763         }
 764         qdisc_tree_reduce_backlog(sch, drop_count, drop_len);
 765
 766         sch_tree_unlock(sch);
 767         return err;
 768 }
 769
 770 static void fq_destroy(struct Qdisc *sch)
 771 {
 772         struct fq_sched_data *q = qdisc_priv(sch);
 773
 774         fq_reset(sch);
 775         fq_free(q->fq_root);
 776         qdisc_watchdog_cancel(&q->watchdog);
 777 }
 778
 779 static int fq_init(struct Qdisc *sch, struct nlattr *opt)
 780 {
 781         struct fq_sched_data *q = qdisc_priv(sch);
 782         int err;
 783
 784         sch->limit              = 10000;
 785         q->flow_plimit          = 100;
 786         q->quantum              = 2 * psched_mtu(qdisc_dev(sch));
 787         q->initial_quantum      = 10 * psched_mtu(qdisc_dev(sch));
 788         q->flow_refill_delay    = msecs_to_jiffies(40);
 789         q->flow_max_rate        = ~0U;
 790         q->rate_enable          = 1;
 791         q->new_flows.first      = NULL;
 792         q->old_flows.first      = NULL;
 793         q->delayed              = RB_ROOT;
 794         q->fq_root              = NULL;
 795         q->fq_trees_log         = ilog2(1024);
 796         q->orphan_mask          = 1024 - 1;
 797         q->low_rate_threshold   = 550000 / 8;
 798         qdisc_watchdog_init(&q->watchdog, sch);
 799
 800         if (opt)
 801                 err = fq_change(sch, opt);
 802         else
 803                 err = fq_resize(sch, q->fq_trees_log);
 804
 805         return err;
 806 }
 807
 808 static int fq_dump(struct Qdisc *sch, struct sk_buff *skb)
 809 {
 810         struct fq_sched_data *q = qdisc_priv(sch);
 811         struct nlattr *opts;
 812
 813         opts = nla_nest_start(skb, TCA_OPTIONS);
 814         if (opts == NULL)
 815                 goto nla_put_failure;
 816
 817         /* TCA_FQ_FLOW_DEFAULT_RATE is not used anymore */
 818
 819         if (nla_put_u32(skb, TCA_FQ_PLIMIT, sch->limit) ||
 820             nla_put_u32(skb, TCA_FQ_FLOW_PLIMIT, q->flow_plimit) ||
 821             nla_put_u32(skb, TCA_FQ_QUANTUM, q->quantum) ||
 822             nla_put_u32(skb, TCA_FQ_INITIAL_QUANTUM, q->initial_quantum) ||
 823             nla_put_u32(skb, TCA_FQ_RATE_ENABLE, q->rate_enable) ||
 824             nla_put_u32(skb, TCA_FQ_FLOW_MAX_RATE, q->flow_max_rate) ||
 825             nla_put_u32(skb, TCA_FQ_FLOW_REFILL_DELAY,
 826                         jiffies_to_usecs(q->flow_refill_delay)) ||
 827             nla_put_u32(skb, TCA_FQ_ORPHAN_MASK, q->orphan_mask) ||
 828             nla_put_u32(skb, TCA_FQ_LOW_RATE_THRESHOLD,
 829                         q->low_rate_threshold) ||
 830             nla_put_u32(skb, TCA_FQ_BUCKETS_LOG, q->fq_trees_log))
 831                 goto nla_put_failure;
 832
 833         return nla_nest_end(skb, opts);
 834
 835 nla_put_failure:
 836         return -1;
 837 }
 838
 839 static int fq_dump_stats(struct Qdisc *sch, struct gnet_dump *d)
 840 {
 841         struct fq_sched_data *q = qdisc_priv(sch);
 842         struct tc_fq_qd_stats st;
 843
 844         sch_tree_lock(sch);
 845
 846         st.gc_flows               = q->stat_gc_flows;
 847         st.highprio_packets       = q->stat_internal_packets;
 848         st.tcp_retrans            = q->stat_tcp_retrans;
 849         st.throttled              = q->stat_throttled;
 850         st.flows_plimit           = q->stat_flows_plimit;
 851         st.pkts_too_long          = q->stat_pkts_too_long;
 852         st.allocation_errors      = q->stat_allocation_errors;
 853         st.time_next_delayed_flow = q->time_next_delayed_flow - ktime_get_ns();
 854         st.flows                  = q->flows;
 855         st.inactive_flows         = q->inactive_flows;
 856         st.throttled_flows        = q->throttled_flows;
 857         st.pad                    = 0;
 858
 859         sch_tree_unlock(sch);
 860
 861         return gnet_stats_copy_app(d, &st, sizeof(st));
 862 }
 863
 864 static struct Qdisc_ops fq_qdisc_ops __read_mostly = {
 865         .id             =       "fq",
 866         .priv_size      =       sizeof(struct fq_sched_data),
 867
 868         .enqueue        =       fq_enqueue,
 869         .dequeue        =       fq_dequeue,
 870         .peek           =       qdisc_peek_dequeued,
 871         .init           =       fq_init,
 872         .reset          =       fq_reset,
 873         .destroy        =       fq_destroy,
 874         .change         =       fq_change,
 875         .dump           =       fq_dump,
 876         .dump_stats     =       fq_dump_stats,
 877         .owner          =       THIS_MODULE,
 878 };
 879
 880 static int __init fq_module_init(void)
 881 {
 882         int ret;
 883
 884         fq_flow_cachep = kmem_cache_create("fq_flow_cache",
 885                                            sizeof(struct fq_flow),
 886                                            0, 0, NULL);
 887         if (!fq_flow_cachep)
 888                 return -ENOMEM;
 889
 890         ret = register_qdisc(&fq_qdisc_ops);
 891         if (ret)
 892                 kmem_cache_destroy(fq_flow_cachep);
 893         return ret;
 894 }
 895
 896 static void __exit fq_module_exit(void)
 897 {
 898         unregister_qdisc(&fq_qdisc_ops);
 899         kmem_cache_destroy(fq_flow_cachep);
 900 }
 901
 902 module_init(fq_module_init)
 903 module_exit(fq_module_exit)
 904 MODULE_AUTHOR("Eric Dumazet");
 905 MODULE_LICENSE("GPL");